In this fascinating book, one of the world's most eminent developmental biologists discusses some of the exciting new insights into how genes control development. Walter Gehring describes in vivid detail his essential contributions to the landmark discovery of the homeobox, a characteristic DNA segment found in the genes of all higher organisms from the fruitfly to humans, and he explains how this has provided the key to our modern understanding of development and evolution. The book thus becomes not only a lucid discussion of genetics but also an engaging description of the art of scientific investigation. Gehring begins his story by looking at the work of the many researchers who laid the foundation for the fields of molecular, cellular, and developmental biology, providing insightful vignettes of past and present investigators. He then describes his laboratory's hunt for the gene that caused odd mutations in the fruitfly-in which, for example, antennae on the head were transformed into legs. He explains that researchers eventually found that the same master control genes that dictate the body plan in flies also pattern human bodies, limbs, hands, heart, and brain. And he illustrates the universality of the genetic control of development by describing the development of the eye; eyes as different as those of humans, squids, and flies, he shows, develop under the same master control gene.